SPACE SHUTTLE PHASE-A DESIGNS [1969]
Notes:
By mid-1969, the ambitious new NASA Administrator, Tom Paine, had proposed an extensive manned space exploration program as the logical follow-on to Apollo. A new modular, reusable space transportation system consisting of the space shuttle as well as interplanetary “space tugs” and space stations would be required to set up bases on the Moon and Mars during the 1970s and 1980s. The first major goal was now a 12-man space station by 1975 and NASA awarded $2.9-million study contracts to North American Rockwell and McDonnell-Douglas in July 1969.
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George Mueller's “space shuttle” effort also appeared to be picking up speed as the Apollo project grew to a close. NASA awarded four $0.3-million space shuttle / integral launch & reentry vehicle “phase-A” study contracts to North American Rockwell, McDonnell-Douglas, Lockheed and General Dynamics in January 1969. Martin Marietta's bid was rejected, but the company nonetheless decided to participate using its own funds. The range of possible concepts was very large and some 120 different permutations were investigated by the contractors. The requirements called for “Integral Launch & Reentry Vehicles” having a 12-crew capability, 720km reentry crossrange, and a 2.268-22.68t payload capability by 1974. The most important mission was expected to be space station resupply payloads weighing about 11,340kg.
In April 1969, Mueller set up a NASA space shuttle task group headed by LeRoy Day to evaluate potential uses of the vehicle. The shuttle requirements had changed considerably as a result of the new post-Apollo program which required a total of 546 shuttle launches in 1975-85. In May, Mueller instructed the task group to increase the payload capability to 22,680kg to comply with US Air Force requirements, but also because there would be a need to launch vast quantities of low-density rocket propellants into Earth orbit for future space stations in geostationary and lunar orbit. The mission requirements also grew significantly more complex and diverse (see table) as the Shuttle had to be capable of launching unmanned satellites and spaceprobes as well.
An important result of Tom Paine's “bold thinking” and cost-is-no-object approach was that only fully reusable VTHL TSTO concepts were considered because they offered the lowest cost per flight and better operability, high payload capability and flexibility. NASA directed its Phase A contractors to concentrate on fully reusable shuttle concepts from August 1969 onwards after the Shuttle task group had investigated the potential life-cycle costs of three classes of 22,680-kilogram payload RLVs. An advanced low-cost expendable rocket plus reusable spacecraft would have cost an estimated $2.5 billion (=$11.35B in 1999 dollars) to develop and $43.1 million (=$195.7M, or $8600/kg in FY'99 $) per launch. The ILRV/Starclipper-type partially reusable SSTO would have had a development cost of $3.9B (=$17.7B in FY'99 $) and the cost per launch was $5.3-12.6M (=$24.1-57.2M / $1000-2500/kg) depending on the production cost of the expendable propellant tanks. Finally, NASA estimated that a simple fully reusable TSTO configuration such as the GD Triamese would have a development cost $4.5B (=$20.5B at 1999 economic conditions) but the cost per launch would only be $3.2 million (=$14.5M in FY'99 $s, or $640/kg).
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“NASA Space Shuttle Summary Report”-- Revision 1, July 31, 1969
“Characteristics of the Space Shuttle” -- Jean & Scott, AAS 1970/vol.28/p.141